It has previously been known to use polyamino acid-type materials and polyglycolic acid-type materials (for example, polylactides) for use in physiological environments, especially for sutures which degrade into physiologically-tolerable degradation products. Some of these materials have been suggested for use as medicinal implants. However, it has proved difficult or impossible to achieve both relatively short-term and straight-line release-rate characteristics from matrices formed of such polymer products. Moreover, these products are relatively expensive.
Therefore, the problem facing the present inventors was one of providing physiologically-tolerable polymers which could be advantageously utilized in making improved products for use in physiological environments.